Olefin-Supported Cationic Copper Catalysts for Photochemical Synthesis of Structurally Complex Cyclobutanes

The sole method available for the photocycloaddition of unconjugated aliphatic alkenes is the Cu-catalyzed Salomon-Kochi reaction. The [Cu(OTf)](2).benzene catalyst that has been standard in this reaction for many decades, however, is air-sensitive, prone to photodecomposition, and poorly reactive towards sterically bulky alkene substrates. Using bench-stable precursors, an improved catalyst system with superior reactivity and photostability has been designed, and it offers significantly expanded substrate scope. The utility of this new catalyst for the preparation of sterically crowded cyclobutane structures is highlighted through the preparation of the cores of the natural products sulcatine G and perforatol.

Automated summary

The sole method available for the photocycloaddition of unconjugated aliphatic alkenes is the Cu-catalyzed Salomon-Kochi reaction. A new catalyst system with superior reactivity and photostability has been designed, offering significantly expanded substrate scope and highlighted through the preparation of the natural products sulcatine G and perforatol.